Infants born <30 wks postmenstrual age (PMA) experience the potentially devastating brain injuries associated with immaturity, hypoxic insults, and inflammatory exposures. These infants are at high risk for developing neuromotor, cognitive, and behavioral impairments that persist through adulthood. However, for the majority of infants, there is no reliable method during their stay in the Neonatal Intensive Care Unit (NICU) to distinguish infants who will go on to develop later impairments from those who will not. There is increasing evidence that neonatal neurobehavioral assessments may predict developmental outcome in at risk and preterm populations. The overarching goal of this study is to determine which infants born <30 wks PMA are at greatest risk for impaired development using a neurobehavioral assessment (the NICU Network Neurobehavioral Scale or NNNS) and a medical risk score. The ability to identify infants at greatest risk addresses a major public health problem and could lead to targeted interventions to reduce or ameliorate later deficits, and more effectively allocate limited resources. We plan to administer the NNNS to 1060 infants born <30 wks PMA during their NICU stay at 7 sites participating in the Vermont-Oxford Network (VON). This will enable us to benefit from the VON infrastructure and medical information collected during neonatal hospitalization, including structural brain abnormalities, infections, an respiratory illnesses. Neurodevelopmental follow-up at 23 +2 months adjusted age will include the Bayley-III, Child Behavior Checklist, Modified Checklist for Autism in Toddlers, and prevalence of cerebral palsy. Our Aims are to determine: 1) if abnormalities on the NNNS will identify infants with impairment at 23 months 2) the association between the cumulative medical risk index, and NNNS scores at 36 wks PMA (or at discharge from the NICU) in infants born <30 wks PMA and 3) the role of post-discharge caregiving environment factors in explaining associations between medical conditions, NNNS scores and 23 month outcomes.